Hepatic triglyceride lipase is thought to play a major role in the catabolism of lipoprotein remnants. However, the major evidence for this involvement is circumstantial and estimates of activity from postheparin plasma are directly opposite to what one would predict from the model of chylomicron clearance. The proposed study is designed to determine directly if hepatic triglyceride lipase plays an important role in remnant removal. Hepatic triglyceride lipase will be purified from postheparin plasma or liver tissue and characterized. The purified material will then be used to produce specific antisera. Since the liver perfusion system can be used to investigate chylomicron remnant uptake and binding, the liver perfusion system will be used to examine the effect of inhibiting hepatic triglyceride lipase with specific antibodies on the ability of the liver to hydrolyze remnant triglyceride. The effect of the specific antisera to hepatic triglyceride lipase on remnant uptake and binding also will be examined.